tl;dr

• Mixed mode assembly (a feature of .NET binaries), involving both C# as well as C++ code in the same executable
• Code flow jumps between both C#/C++ frequently to make analysis harder
• SEH mechanism triggered in C++ code, which uses SEH trampoline to make debugging harder
• SEH triggered once again in C#, which is handled by C++
• VM bytecode is decrypted loaded by C#
• VM checks input in 4 ways: CRC32 hash (2 byte pairs), RC4 encryption, rolling XOR and byte by byte checks

tl;dr

• Whisper model converts audio to text
• text is passed through subprocess and not sanitized
• difficult to generate a command injection through manual voice
• Need to invert the Neural network that will generate the audio file we need
• Implement Gradient descent based inversion to find input for target output.
• Generate the audio file and send, get flag!

tl;dr

• ECDSA signing server with biased nonce
• Exploitation by modelling a EHNP instance and using z3 Solver for breaking Mersenne Twister

tl;dr

• memcpy in CPY goes out-of-bounds of VM stack.
• Abuse memcpy to copy the register struct to stack and modify the values using stack operations and register operations.
• Copy values back to the register struct, modifying the VM stack bp and sp registers.
• This migrates the VM stack to wherever you want, gaining arbitrary read and write.
• Leak environ pointer to get stack leak.
• Migrate VM stack to main function’s stack to overwrite return address with ROP chain or one-gadget.

tl;dr

• Analysis of different types of malware in a linear storyline
• Windows timelining
• Analysis of Rootkit, Ransomware, C2 Framework, Process Hollowing, Persistence, and more

tl;dr

• appending same bytes to an existing collision results in a collision as well
• reusing nonce leads to secret leak

tl;dr

• Timing-based attack on the double-and-add algorithm to recover secret value d
• Predict pseudo-random value using the NSA backdoor on Dual_EC_DRBG

tl;dr

• Challenge 2 of Batman Investigation series
• Ransomware Investigation
• Rust based Ransomware Analysis with process dump analysis to recover the randomly generated decryption vector and windows malware analysis
• Recovering from a ransomware attack

Full solution of Batman Investigation II - Gotham Underground Corruption from bi0sctf 2024

tl;dr

• Challenge 1 of Batman Investigation series
• Memory Forensics - WinDBG Dump Debugging - Malware Analysis - Incident Response - Threat Hunting

tl;dr

• Analysis of eBPF assembly
• Simple optimization